NEB Exam Q: POISONING " Animal Poisoning " | Forensic Medicine

Classification of snakes

-Poisonous

Poisonous

A. Colubridae
Elapidae
Kobra
Krait
Mamba

B. Hydrophidae
Viperadae
Rattle snake
Pit vipers
Russel viper

Elapids: (Cobra, Krait)

• Secrete neurotoxin- leads to local burning pain, muscular weakness, spreading paralysis, slow labored breathing, death is usually due to respiratory failure
• Head is small
• Pupils are round
• Fangs are short, fixed and grooved
• Cobra is found everywhere except Europe
• Cardiotoxin found particularly in cobra venom is toxic to heart
• Cobra has a hood which on the dorsal side often bears a double or single spectacle mark
• Cobra grows to a length about 2 m.
• Cobra venom fatal dose- 15 mg
• Krait has a single or double white bands across the back and a creamy white belly
• Kraits are nocturnal in habit
• Kraits venom fatal dose- 6 mg

Vipers

• Secrete vasculotoxic venom- intense local pain, swelling, ecchymosis and discoloration of surrounding tissue, oozing of bloody serum rapid feeble pulse, hemorrhage from natural orifice, cold and clammy skin, loss of consciousness, death from shock
• Consists of pit vipers and pit less vipers
• Pits are situated between the eye and nostrils
• Head is big and triangular
• Pupil is vertical
• Fangs are long, movable and canalized
• Can bite through clothes
• Pit vipers are seldom dangerous but the russel viper, which is pitless viper, is dangerous.

Sea snakes:

• Secrete myotoxic venom- generalized pain and stiffness, brown colored urine due to myoglobinuria, hyperkalaemic symptom, death due to respiratory failure
• Small head and flat tail
• Found in the vicinity of sea coast
• Most of them do not bite

Q: Difference b/w poisonous and non-poisonous?
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Poisonous:

• Belly scales are large and cover entire belly
• Fangs are hollow like hypodermic needles
• Tail is compressed
• Two long fangs are present
• Usually nocturnal
• Head scales are small with enlarged central row of scales on back

Non-poisonous:

• Small, do not cover the entire belly
• Fangs are short and solid
• Tail is not much compressed
• Several small teeth
• Not so nocturnal
• Head scales are large